Which term describes the process of aging spirits in barrels to develop flavor?

The process of aging spirits in barrels to develop flavor is referred to as maturation. During maturation, the spirit interacts with the wood of the barrel, allowing for the extraction of various compounds that enhance the flavor profile. This interaction introduces flavors from the wood, such as vanilla, caramel, and spices, while also allowing the spirit to mellow and develop complexity over time. Additionally, maturation involves the slow evaporation of some alcohol and water, referred to as the "angel's share," which can further concentrate the flavors in the spirit.

Fermentation, on the other hand, is the initial stage where sugars are converted into alcohol by yeast; oxidation is a chemical reaction that can occur during aging but is not the primary focus of barrel aging; and distillation is the process of heating a fermented liquid to separate alcohol from water and other components. Therefore, the term maturation specifically encapsulates the aging process that transforms the raw spirit into a smooth, flavorful beverage.